Determination of large current with Optical Heterodyne Interferometer
| Autor: | Yu-Bin Lin, 林郁彬 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 In order to maintain the qualities and performance of the electric power system, to examine and measure the current and voltage in the instruments of the system are important. The reliability and requirements of the specification are high for those instruments, which have always been exposed in a very high electromagnetic field, so that to shield the detection system from the interference of electromagnetic wave is indispensable. Moreover, the insulating arrangement and safe apparatus are significant, especially for the ultra-large current measurement. The current sensors nowadays are inappropriate for the drawbacks of saturation, hysteresis, and easy to interfere. The purpose of this current measuring system is to utilize Faraday effect and optical heterodyne interferometry to measure the current, and to improve the above drawbacks. This current measuring system consists of three parts: (1) the optical path arrangement, (2) the current sensing part, and (3) the signal detection part. The optical path arrangement is composed of a linear polarized light source and Mach-Zehnder interferometer. The current sensing part is composed of a straight conducting wire and a MO glass. The signal detection part is composed of a photon detector, band-pass filter, and a Lock-in amplifier. The detected beat signal is therefore transmitted to a PC with the Labview software to manage the measurements and analysis. We had measured a large DC current to 125A by the system. In our estimation, this system is capable of measuring the DC current to an amount of 80 KA. Since this system is safe and accurate, can measure very large current in real time, we have provided an excellent method for the larger current measurement. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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